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Date:   Thu, 20 May 2021 03:12:02 +0200
From:   Andrew Lunn <andrew@lunn.ch>
To:     Vadym Kochan <vadym.kochan@plvision.eu>
Cc:     "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>, netdev@vger.kernel.org,
        Taras Chornyi <tchornyi@marvell.com>,
        linux-kernel@vger.kernel.org,
        Mickey Rachamim <mickeyr@marvell.com>,
        Vadym Kochan <vkochan@marvell.com>
Subject: Re: [RFC net-next 1/4] net: marvell: prestera: try to load previous
 fw version
Message-ID: <YKW3YhuDSHQtR4Tb@lunn.ch>
References: <20210519143321.849-1-vadym.kochan@plvision.eu>
 <20210519143321.849-2-vadym.kochan@plvision.eu>
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> +static int prestera_fw_get(struct prestera_fw *fw)
> +{
> +	int ver_maj = PRESTERA_SUPP_FW_MAJ_VER;
> +	int ver_min = PRESTERA_SUPP_FW_MIN_VER;
> +	char fw_path[128];
> +	int err;
> +
> +pick_fw_ver:
> +	snprintf(fw_path, sizeof(fw_path), PRESTERA_FW_PATH_FMT,
> +		 ver_maj, ver_min);
> +
> +	err = request_firmware_direct(&fw->bin, fw_path, fw->dev.dev);
> +	if (err) {
> +		if (ver_maj == PRESTERA_SUPP_FW_MAJ_VER) {
> +			ver_maj--;
> +			goto pick_fw_ver;
> +		} else {
> +			dev_err(fw->dev.dev, "failed to request firmware file\n");
> +			return err;
> +		}
> +	}

So lets say for the sake of the argument, you have version 3.0 and
2.42. It looks like this code will first try to load version 3.0. If
that fails, ver_maj is decremented, so it tries 2.0, which also fails
because it should be looking for 2.42. I don't think this decrement is
a good idea.

Also:

> +			dev_err(fw->dev.dev, "failed to request firmware file\n");

It would be useful to say what version you are actually looking for,
so the user can go find the correct firmware.

   Andrew